Double bubble sign in children is seen in all EXCEPT:
**Core Concept**
The double bubble sign is a radiological finding seen on abdominal X-rays or ultrasound in children, characterized by two distinct gas-filled structures seen in the upper abdomen, suggesting an obstruction in the duodenum.
**Why the Correct Answer is Right**
The double bubble sign is classically associated with duodenal atresia or stenosis, where there is an interruption or narrowing of the duodenum, preventing the normal flow of intestinal contents. This leads to accumulation of gas in the stomach and the proximal duodenum, creating the characteristic "double bubble" appearance. The duodenum is the first part of the small intestine, and its obstruction can be due to various causes, including congenital anomalies, intussusception, or external compression.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because pyloric stenosis typically presents with a "single bubble" sign on X-ray, where the stomach is distended with gas, but there is no gas in the small intestine.
**Option B:** This option is incorrect because intestinal obstruction due to volvulus (twisting of the intestine) may not always produce the classic double bubble sign, and the appearance can vary depending on the level and extent of the obstruction.
**Option C:** This option is incorrect because Hirschsprung's disease typically presents with a distended colon and a transition zone between the normal and affected bowel, rather than the double bubble sign.
**Clinical Pearl / High-Yield Fact**
The double bubble sign is a classic radiological finding in duodenal atresia or stenosis, which is often associated with other congenital anomalies, such as Down syndrome or cardiac defects.
**Correct Answer: D. Hirschsprung's disease is not typically associated with the double bubble sign.**